One type of prior art plural compartment package utilizes a bag-in-a-bag type structure for mixing two different materials together. For example, as illustrated within U.S. Pat. No. 3,950,158 which was issued on Apr. 13, 1976 to Rodger L. Gossett, an inner rupturable bag is surrounded by or encased within an outer sealed bag. When a predetermined amount of pressure is applied to or impressed upon an appropriate exterior portion of the outer sealed bag, a seal structure provided within the inner rupturable bag ruptures so as to thereby release the material contained within the inner rupturable bag whereby the contents of the inner and outer bags can then mix together so as to form the desired mixture or compound.
The aforenoted type of prior art plural compartment package structure, however, has several disadvantages. For example, it is not especially economically advantageous since is requires the use of a substantial amount of material in order to fabricate a completed package or bag structure since, in effect, two complete, separate bags are required to be formed in order to constitute the composite package or bag structure. In addition, it has been found that the inner rupturable bag is sometimes difficult to rupture since an inner seal must be broken in order to release the content of the inner bag. It has also proven difficult to fabricate a separating seal that has consistent burst strength since the package or bag structure, and particularly the seal structure thereof, must be fabricated in accordance with a very narrow range of processing conditions comprising variable heating, dwell time, and pressure parameters. If the seal structure is effectively too tight or rigid, that is, has a relatively high burst strength, then the seal will be difficult to burst or will not burst properly, however, on the other hand, if the seal structure is effectively too loose or is not rigid enough so as to exhibit a relatively low burst strength, the seal structure permits migration of the fluids and intermixing thereof in a premature manner whereby premature setting of the bag contents occurs.
In view of the foregoing, the aforenoted parent patent application was directed toward the disclosure of a plural compartment package whereby the aforenoted deficiencies of the prior art type of plural compartment packages would be overcome and rectified and while the plural compartment package disclosed within the noted parent patent application has in fact overcome and rectified the noted deficiencies of the prior art type of plural compartment packages, and wherein further, the plural compartment package of the noted parent patent application has been quite satisfactory from a functional or operational point of view, some difficulties have been encountered in connection with the manufacture of such a plural compartment package. For example, due to the presence of three layers of packaging material forming one peripheral end portion of the laminated composite package, while only two layers of packagin material form an opposite peripheral end portion of the laminated composite package, the pressure levels required in connection with the heat sealing process for forming the heat-sealed peripheral portions of the laminated composite package must necessarily be varied, appropriately adjusted, or controlled in order to accommodate the different thickness dimensions of the laminated composite package within the noted peripheral end regions. If an inappropriate or improper pressure level is impressed upon a particular peripheral en portion or region of the laminated composite package due, for example, to a failure to properly accommodate or compensate for the differences in the thickness dimensions of that particular peripheral end portion or region relative to the opposite peripheral end portion or region, then the heat seal formed within that particular peripheral end portion or region of the package would then be improper, incomplete, or simply insufficient from a seal-integrity point of view, whereby problems may then be encountered in connection with the leakage of the package contents. In addition, the precise adjustment or control of the requisite pressures needed to properly achieve the entire peripheral heat seal region of the composite package, wherein accommodation of or compensation for the different thickness dimensions characteristic of the opposite peripheral end portions or regions of the package must be resolved, is sometimes difficult to achieve, is time-consuming, and tedious.
There is therefore a need, to which the present invention is directed, for a plural compartment package which is not only able to achieve the objectives of the plural compartment package disclosed within the aforenoted parent patent application, whereby the problems, drawbacks, and disadvantages of the known prior art are able to be overcome, but which, in addition, is able to be readily manufactured or fabricated without encountering the aforenoted manufacturing difficulties characteristic of the plural compartment package disclosed within the parent patent application. Still further, there is also a need for a plural compartment package which can achieve consistent burst strength or burst pressure levels so as to facilitate reliable, easy, and proper mixing of the package components.